spopt#

SpectrumOptions.spopt(spectype='', nmode='', elcalc='', modereusekey='', **kwargs)#

Selects the spectrum type and other spectrum options.

Mechanical APDL Command: SPOPT

Parameters:
spectypestr

Spectrum type:

  • SPRS - Single point excitation response spectrum (default). See also svtyp.

  • MPRS - Multiple point excitation response spectrum.

  • DDAM - Dynamic design analysis method.

  • PSD - Power spectral density.

nmodestr

Use the first NMODE modes from the modal analysis. Defaults to all extracted modes, as specified by the modopt and bucopt commands. NMODE cannot be larger than 10000.

elcalcstr

Element results calculation key:

  • NO - Do not calculate element results and reaction forces (default).

  • YES - Calculate element results and reaction forces, as well as the nodal degree of freedom solution.

modereusekeystr

Key for existing MODE file reuse when running multiple spectrum analyses:

  • NO - No spectrum analysis has been performed yet (default).

  • YES - This is not the first spectrum analysis. The MODE file will be reused and the necessary files will be cleaned up for the new spectrum analysis.

Notes

Valid only for a spectrum analysis ( antype,SPECTR). This operation must be preceded by a modal solution ( antype,MODAL) with the appropriate files available. Both the spectrum analysis and the preceding modal analysis must be performed under the same Mechanical APDL version number.

If used in SOLUTION, this command is valid only within the first load step.

Element results are calculated ( Elcalc = YES) only if the element modal results are available (written to the Jobname.mode file with MSUPkey = YES on the mxpand command). For Sptype = SPRS, MPRS, and DDAM, if the element results calculation is activated ( Elcalc = YES) and element modal results are not available, it is deactivated automatically.

For SPRS, DDAM or MPRS analyses, modal responses can be combined and stored directly in the Jobname.rst file during spectrum solution according to the mode combination method command issued ( srss, cqc, etc.) for Elcalc = YES. This can save significant time compared to the method for Elcalc = NO, which requires generating the file of POST1 commands ( Jobname.mcom file) to be read in POST1 to do the mode combinations. For details and example usage, see Spectrum Analysis, and Example: Multi-Point Response Spectrum (MPRS) Analysis.

This command is also valid in PREP7.